A power metal-oxide-semiconductor field-effect transistor (MOSFET) may be used to implement a voltage-controlled semiconductor switch that can handle relatively significant levels of power without breaking down. One type of power MOSFET is a current sensing power MOSFET. A current sensing power MOSFET may be used to implement a voltage-controlled semiconductor switch and to measure a load current that is flowing through the power semiconductor switch in a relatively efficient manner without requiring the use of separate current sensing resistors.
A current sensing power MOSFET may split a load current flowing through the current sensing power MOSFET into a main current that flows through a main current path and a sensing current that flows through a sensing current path. The ratio of the amplitude of the load current to the amplitude of the sensing current may be referred to as the kILIS factor of the current sensing power MOSFET (alternatively referred to as the “load current-to-sensing current ratio” of the current sensing power MOSFET).
If the kILIS factor of a particular current sensing power MOSFET is known, then measurement of the sensing current may be used along with the kILIS factor to determine the amount of load current flowing through the switch. Thus, the degree of accuracy of a load current measurement is dependent upon the degree of accuracy to which a current sensing power MOSFET actually produces a specified kILIS factor. Causing a current sensing power MOSFET to produce a specific kILIS factor with a relatively high degree of accuracy can present significant challenges.